Ignition apparatus



July 17, 1934. C S, R 1,967,078

IGNITION APPARATUS Original Filed Sept. 14, 1931 Patented July 17, 1934 IGNITION APPARATUS Charles Hall Davis, Jr., Anderson, Ind., assignor,

by mesne assignments, to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application September 14, 1931, Serial No. 562,655 Renewed July 30, 1932 10 Claims.

This invention relates to ignition apparatus for internal combustion engines and more particularly to the type of ignition timer and distributor unit which is driven at one-half engine cycle speed,

namely, at one-fourth engine speed for a four cycle engine or at one-half engine speed for a two cycle engine. One type of such ignition timer and distributor unit is disclosed in the copending application of John T. Fitzsimmons, Serial Number 566,419 filed Oct. 2, 1931 now Patent 1,928,222, Sept. 26, 1933.

It is an object of the present invention to provide an ignition timer and distributor unit which can be operated at one-fourth engine cycle speed and which is adapted to fire an engine having an odd or even number of engine cylinders. In this connection it is a further object of the invention to provide an ignition timer and distributor unit of the type referred to and which will have a dis- 20 tributor head in which the distributor spark plug terminal posts will be arranged in the conven- 4 tional manner according to the firing sequency of the engine.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing wherein a preferred embodiment of one form of the present invention is clearly shown.

In the drawing:

The figure of the drawing is a wiring diagram illustrating the present invention. I

Referring to the drawing which illustrates an ignition timer and distributor unit for a three cylinder internal combustion engine said ignition unit being driven by the engine at one-half cycle speed, namely, one-fourth engine speed for a four cycle internal combustion engine or one-half engine speed for a two cycle engine. The drive shaft of the timer unit which is driven by the engine at the speed referred to is designated by the numeral 20. The shaft 20 drives a timer cam 21 whose lobes number twice the number of engine cylinders, for-example, six lobes for a three cylinder block 22 attached together with a leaf spring con- 65 The ignition coil secondary 36 is grounded through engine. The cam 21 cooperates with a rubbing the switch 33 and the battery 34 and is connected by wire-37 with the central terminal 38 of a. distributor 40 having a head 39 carrying as many distributor spark plug terminal posts 41 as there are engine cylinders, for example, three posts for a three cylinder engine. The central terminal 38 is electrically connected with a distributor rotor 42 driven by shaft 20. The rotor 42 has two diametrically opposite rotor arms R1 and R2.

The distributor post 41 which appears uppermost in the drawing is designated byindicia Pl-Rl and (P1R2). The indicia P1--R1 designates that this post is connected with spark plug SP1 and that a sparking impulse is con-' ducted thereto by rotor arm R1 during the firsthalf revolution of the shaft 20. The indicia in brackets, namely (PL-R2) means that post 41 which is connected with spark plug SP1 is provided with a sparking impulse by rotor arm R2 during the second half revolution of shaft 20. 75 Similarly, the right hand post 41 in the drawing is designated by indicia P3--R1 to indicate that this post is connected with spark plug SP3 and that rotor R1 distributes a sparking impulse thereto during the first half revolution of shaft 20. The indicia (P3-R2) designates that during the second-half revolution of shaft 20 the rotor arm-R2 operates to conduct a sparking impulse to this post for the purpose of providing a spark at spark plug SP3. Similarly, the left hand post 41 is designated by indicia P2R2 to designate that this spark plug post is'connected with spark plug SP2 and that rotor arm R2 operates to conduct a sparking impulse to this distributor post 41 during the first half revolution of shaft 20; and the indicia (P2R1) indicates that during the second half revolution of the shaft 20 the rotor arm R1 operates to conduct a sparking impulse to this distributor post.

It is therefore apparent that the present invention includes a distributing device of novel construction for use with an ignition timer in an: ignition timer distributor unit which is adapted to be driven at one-half cycle speed and to provide ignition for use in engines having an odd number of cylinders. The present invention contemplates that the distributor shall have its distributor posts'arranged in the conventional manher about the entire periphery of the distributor effective alternatively to distribute sparking impulses to the distributor posts P1, P2 and P3. By such a construction and arrangement it is possible to use a distributor head having its terminals, to which the spark plug wires are connected, arranged in the usual manner, the spacing being symmetrical for an engine having a symmetrical firing sequence.

It is apparent that the present invention can be applied to engines having a number of cylinders other than three as disclosed in the drawing. For example, if the engine has five cylinders, then the number of lobes of the cam 21 will be ten. The distributor 40 will have five posts 41 arranged in a circular row and cooperating with a double end rotor 42 such as shown in the drawing. If the ignition timer distributing unit is to be used with a reversible engine such as a marine engine, then the ends of the rotor arm should be elongated as shown in the drawing in order to provide for either direction of rotation.

It is apparent from the foregoing description of the construction and mode of operation of ignition apparatus embodying the present invention that the present invention contemplates a distributor head having a center terminal and is derived by subtracting from the rotor arm spacing is an integer. The following tabulation shows the values of S, B and L for engines having different numbers, N, of explosion periods during each engine cycle.

circularly arranged posts equal to N, the number of explosion periods occurring during an engine cycle, said circularly arranged posts being connected respectively to spark gaps, and a distributor rotor connected with the center terminal and having.N1 distributing conductor arms and turning at the rate of revolution during each engine cycle, said arms and posts being so arranged that the arms function alternately but each not more than once in succession during an engine cycle. It will be noted that those posts which are served by a certain arm during one engine cycle are served by another arm during the next engine cycle. The induction means which supplies the center contact with a sparking impulse each time a rotor arm is adjacent a post is controlled by a circuit interrupter means so constructed and arranged as to give a sparking impulse for each Ex losion Sparking Ratio of peri ds dur- Number of interval in rotor speed Number %a mg each (illb rote; degiiees off to 1engined es c c es ee gum cyc 8 mm m r otg r 0 y p B=No. of breakers operating alternately 360 1 L L L L L L N N -N N-l B=1 =2 =a) =4 (B=5) =6) 3 2 60 6 3 2 1 4 3 30 5% 12 6 4 3 2 5 4 18 }4 20 10 5 4 6 5 12 9%. 30 15 i0 6 5 7 6 8 /1 52 42 g 7 8 7 6 1 3 56 9 s s is 72 36 24 18 12 1 15 10 9 4 $6 90 45 30 18 15 While the form of embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. Ignition apparatus for an engine having an odd number of engine cylinders and comprising a drive shaft operated by the engine at one-half engine cycle speed, a cam driven by the shaft and having lobes numbering twice the number of engine cylinders, a distributor head having its posts arranged in a circular row and equalling in number the number of cylinders, and a double end rotor driven by the shaft and having its rotor arms diametrically opposite.

2. Ignition apparatus for an engine having an odd number of engine cylinders and comprising a drive shaft operated by the engine at one-half engine cycle speed, a cam driven by the shaft and having lobes numbering twice the number of engine cylinders, a distributor head having its posts arranged in a circular row and equalling in number the number of cylinders, and a doubleend rotor the arms of which are operative alternately to distribute sparking impulses.

3. Ignition apparatus for an internal combustion engine, a drive-shaft operated by the engine at one-half engine cycle speed, sparking impulses generating means operated bysaid shaft and generating during one-half turn of the shaft a sequence of impulses required during one engine cycle, and means for distributing said impulses and comprising a head carryingposts to which the engine spark plugs are connected and a rotor having a plurality of arms operating alternately to distribute sparking impulses.

4. Ignition apparatus for an internal combustion engine having N explosion periods during an engine cycle comprising, in combination, a distributor comprising a head having N posts ar: ranged circularly and connected respectively with engine spark gaps, a rotor carrying N "1 distributing conductor arms and operating at the rate of revolution during each engine cycle, said arms moving past said posts and said arms and posts being so arranged that the arms function alternately but each not more than once in succession during an engine cycle, and means for providing an arm with a sparking impulse whenever it passes adjacent to a post.

5. Ignition apparatus for an internal combustion engine having N explosion periods during an engine cycle comprising, in combination, a distributor comprising a head having N posts arranged circularly and connected respectively with engine spark gaps, a rotor carrying N-1 distributing conductor arms and operating at the rate of revolution during each engine cycle, said arms moving past said posts and said arms and posts being so arranged that the arms function alternately but each not more than once in succession during an engine cycle and that those posts which are served by a certain arm during one engine cycle are served by another arm during the next engine cycle, and means for providing an arm with a sparking impulse whenever it passes adjacent to a post.

6. Ignition apparatus for an internal combustion engine having N explosion periods during an engine. cycle comprising, in combination, a distributor comprising a head having a center terminal and having N posts arranged circularly and equiangularly and connected respectively with engine spark gaps, a rotor connected with the center terminal and having N-l equiangularly spaced distributing conductor arms and operating at the rate of passes adjacent to a post.

7. Ignition apparatus for internal combustion engines having N explosion periods during an engine cycle comprising, in combination, a distributor comprising ahead having a center terminal and posts arranged circularly and equiangularly and connected respectively with engine spark gaps, a rotor connected with the center terminal and having N-1 equiangularly spaced, connected arms and operating at the rate of 360 N -N and said arms and posts being so arranged that the arms function alternately but each not more than once in succession during an engine .cycle and that those posts which are served by a certain arm during one engine cycle are served by another arm during the next engine cycle, and means for providing an arm with a sparking impulse whenever it passes adjacent to a post.

8. Ignition apparatus for internal combustion engines having N explosion periods during an engine cycle comprising, in combination, a distributor comprising a head having a center terminal and posts arranged circularly and equiangularly and connected respectively with engine spark gaps, a rotor connected with the center terminal 100 and having N-1 equiangularly spaced, connected arms and operating at the rate of F 1 revolution during each engine cycle, one of said 10 arms moving past one of said posts each and said arms and posts being so arranged that the arms function alternately buteach not more than once in succession during an engine cycle and that those posts which are served by a' certain arm during one engine cycle are served by 115 another arm during the next engine cycle, and means for providing an arm with a sparking impulse whenever it passes adjacent to a post, said sparking impulse means comprising B circuit breakers operated by a cam having m BS lobes and rotated by the engine at the rate of revolution during each engine cycle, B being a number such that the quotient of is an integer.

9. Ignition apparatus for an internal combustion engine having three explosionperiods during an engine cycle comprising in combination, a distributor comprising a head having three posts arranged circularly and connected respectively with engine spark gaps, a rotor carrying two distributing conductor arms and turning at the rate of one half a revolution during each engine cycle, said arms moving past said posts and said arms and posts being so arranged that the arms function alternately but each not more than once in succession during an engine cycle, and that those posts which are served by one arm during. one engine cycle are served by the other arm during the next engine cycle, and means for providing an arm with a sparking impulse whenever it passes adjacent to a post.

cycle, and means for providing an arm with a sparking impulse each 60 of rotor rotation, said means comprising B circuit breakers operated upon alternatelv by a cam having lobes, B being equal to 1, 2, 3 or 6.

CHARLES HALL DAVIS, JR. 

